Percent decimals and fractions.notebook

Percent decimals and fractions.notebook
Percents, Decimals and Fractions
Introduction to Percents ­ Watch these 3 videos!
February 18, 2015
3/4
75%
0.75
Khan Academy:
1. Describing the meaning of percent 2. Converting percents to decimals
3. Representing a number as a decimal, percent and fraction
GOOD EXPLANATION: Math Goodies The meaning of percent (questions at end)
Try this!
Using the hundredths grids, shade in the following amounts. Write the percent, then equivalent representations using a decimal, proper fraction and simplified fraction.
50%
25%
75%
80%
Practice Game:
Math Goodies: A practice game!
Worksheets for Extra Practice:
Math Goodies: Worksheet for extra practice
Math Goodies: The answers :­)
Percent decimals and fractions.notebook
1. To convert a fraction into a percentage, you need a denominator of 100.
So how do we convert a fraction such as 10 into a percentage?
25
Two ways!
A) Create an equivalent fraction where the denominator is 100.
10 = ? 25 100 * 25 x 4 = 100 SO multiply the numerator by the same number.
* 10 x 4 = 40 SO 40 = 40%
100
B) We can cross multiply! 10 = ? 25 100 * Multiply 10 x 100 = 1000
* Divide 1000 by 25
* Answer is 40, so 40 100 = 40%
2. How do I convert a decimal number to a percent?
Let's start with 0.84. Look at the digits in the tenths and hundredths columns.
We know there are 84 hundredths = 84/100 = 84%. But what about if our number is 0.841? What about the 1 thousandth? We include it as a decimal after the 84 = 84.1%
This means it is 1 tenth of 1 hundredth (which is a thousandth).
What if I have a whole number in my decimal?
Look at this example: 1.84
We know we have 84 hundredths or 84%. The whole number 1 represents 100 hundredths, so 100 hundredths = 100%.
So our percent becomes 184%
3. Let's convert a percent to a decimal number! Look at the following 11.6%. The 11 represents 11 hundredths or 0.11
The .6 represents 6 tenths of 1 hundredth (which is 6 thousandths)
so our decimal becomes 0.116
February 18, 2015
Percent decimals and fractions.notebook
February 18, 2015
Problems: 1. Place these fractions, decimals and percents on the number line. 25%, 1.55, 2/3, 75%, 1.9, 1 1/4 0­­­­­­­­­­­­­­­ ½ ­­­­­­­­­­­­­­­­1 ­­­­­­­­­­­­­­­1 ½ ­­­­­­­­­­­­­­­2
100%
2. Chris, Paul and Carla share the cost of renting a video game. • Chris pays 0.4 of the cost. • Paul pays 36% of the cost. • Carla pays the remainder of the cost. What fraction of the cost does Carla pay? a 6/25
b 9/25
c 19/25
d 24/25
3. Mr. Price’s class collects a total of 1943 pennies over a period of 4 weeks. Samantha brings 125 pennies each week. Approximately what percent of the total number of pennies collected does Samantha bring? a 10% b 25% c 50% d 75% 4. Jade goes shopping for a pair of jeans. She sees one pair that costs $39.99 with a 25% discount.
A second pair costs $29.99 with a 15% discount. Which pair will cost her less?
For help with discount problems, go to the following site:
Practice Problems:
Math Goodies: Real Life Problems ­ Sale, Sale, Sale! Percent decimals and fractions.notebook
Practice Problems!
Textbook: page 369 ­ #5, 7, 8, 9
page 370 ­ A to F
page 371 ­ #5, 6
page 373 ­ #5, 7
February 18, 2015